The present application claims priority upon Japanese Patent Application No. 2001-222042 filed on Jul. 23, 2001, which is herein incorporated by reference.
1. Field of the Invention
The present invention is related to an article conveyor device. In particular, the present invention relates to an article conveyor device having an input shaft supported movably to a housing, an output shaft supported movably in respect to the housing, a first cam to oscillate the output shaft by cooperating with the input shaft, and a second cam different to the first cam, to reciprocate the output shaft by cooperating with the input shaft, and an article conveyor portion which oscillates and reciprocates with the output shaft.
2. Related Art
Conventionally, there has been proposed various devices to convey and align articles such as so-called unpackaged parts, and to feed them one by one. These devices are generally referred to as a xe2x80x9cparts feederxe2x80x9d. There are various types of parts feeders such as a vibratory type, a rotating type, an oscillating type, a belt type, and a shaking type, in which a vibratory parts feeder is the most common. This vibratory parts feeder is a device where articles to be conveyed are placed on a vibrating surface, and by use of a relative slip and jump phenomenon between them, alignment and conveying of the articles are performed.
An exemplary structure of a vibratory parts feeder is described referring to FIG. 8. As shown in FIG. 8, a bowl 100 is supported in a state biased by a few pairs of supporting springs 104 in respect to a base 102. Further, the base 102 is provided with an electromagnet 106, and the bowl 100 may be drawn near by this electromagnet 106. Therefore, if an alternating voltage with a predetermined frequency is applied to the electromagnet 106, the bowl 100 vibrates according to the frequency. In this way, the article (work) W accommodated in the bowl 100 is appropriately aligned and conveyed and fed from a gate 100a one by one.
However, a vibratory parts feeder having such a structure has various problems. For example, the problems are such as a lot of time in adjustment, magnetization of work, and generation of noise. In particular, regarding noise, in the case of a vibratory parts feeder with the above described structure, the work is made to jump in respect to the bowl 100 and conveyed, thus noise is generated when the work lands on the bowl 100.
In view of the above problems, there is proposed a vibratory parts feeder using a cam, for example, such as that shown in Japanese Unexamined Patent Publication No. Sho 58-6810 (Japanese Examined Patent Publication No. Sho 63-24891). A device described therein has a bowl supported rotatably about a center shaft. The bowl is rotated while horizontally vibrated by a cam so that a significant difference in accelerations for back and forth strokes exists, so as to convey the work inside it using friction force and inertial force.
In this device, since a cam is used, and the bowl horizontally oscillates and does not reciprocate in an up-and-down direction, the work does not jump on the bowl, and thus this device is advantageous in that a conventional problem regarding noise may be eased. However, since with this device the bowl horizontally oscillates and does not reciprocally move in the up-and-down direction as described above, the work on the bowl is always contacted toward the bowl with a predetermined force by gravity.
In order to efficiently convey the work in the bowl, it is preferable for a contact pressure of the work in respect to the bowl to vary depending on a direction of the bowl movement, i.e., in the case the bowl moves in the conveying direction of the work, and in the case the bowl moves in an opposite direction to the above. In other words, it is preferable at the time the bowl moves in the conveying direction of the work, to make the work contact against the bowl with a stronger force, to suppress slipping of the work in respect to the bowl and to actively convey the work, whereas, it is preferable at the time the bowl moves in an opposite direction to a conveying direction of the work, to make the work contact against the bowl with a slighter force, to encourage the work to slip in respect to the bowl and to suppress the work from returning to an opposite direction of the conveying direction of the work.
In view of the above problems, one object of the present invention is to provide an effective article conveyor device having a first cam, and a second cam different to the first cam.
One aspect of the present invention for achieving the above and other objects is an article conveyor device conveying an article, comprising:
an input shaft movably supported in respect to a housing;
an output shaft movably supported in respect to the housing;
a first cam to make the output shaft oscillate by cooperating with the input shaft;
a second cam different to the first cam, to make the output shaft perform a reciprocating motion by cooperating with the input shaft; and
an article conveyor portion oscillating and performing a reciprocating motion with the output shaft.
For example, the first cam may be a roller gear cam,
the output shaft may be provided with a plurality of cam followers contacting the roller gear cam, and
the roller gear cam and the cam followers may constitute a roller gear cam mechanism.
The output shaft may be provided with a contacting portion contacting the second cam, and the contacting portion may be contacting a peripheral surface of the second cam as biased towards the input shaft by the biasing member.
At the time the output shaft is oscillated by the first cam, the contacting portion may slide in respect to the second cam as contacting the second cam.
The output shaft may be provided with a concave engaging portion which engages the second cam, and
the engaging portion may be engaged with the second cam of the input shaft.
At the time the article conveyor portion is oscillated by the first cam, the engaging portion may slide in respect to the second cam as engaged with the second cam.
The oscillation may be in a horizontal direction, and the reciprocating motion may be in a vertical direction.
At the time the article conveyor portion is oscillated to move from a first position in a conveying direction of an article to a second position, and to move from the second position to an opposite direction in a conveying direction of the article to the first position,
a time taken for the article conveyor portion to move from the first position to the second position may be longer than a time taken for the article conveyor portion to move from the second position to the first position.
In an oscillating motion of the article conveyor portion, the article conveyor portion may perform constant speed travel for a predetermined time, during a time period since movement of an article in a conveying direction is started until the movement is ended.
At the time a speed of the article conveyor portion directed upwards is increasing, the article conveyor portion may perform the constant speed traveling in an oscillating motion.
At the time the article conveyor portion is moving in a direction opposite to a conveying direction of an article in an oscillating motion, a speed of the article conveyor portion directed downwards may increase.